Video transducer system and cartridge therefor

ABSTRACT

A video tape cartridge of endless loop configuration capable of tape speeds of 120 inches per second while providing one hour or more of continuous playing time on 1/4 inch width tape. In an illustrative embodiment the tape drive is steady enough so that the reproduced signal can be coupled to the antenna circuit of a home television receiver without modification of the conventional synchronizing circuits.

nited States Patent 1191 Y Camras [111 3,849,797 [451 Nov. '19, 1974VIDEO TRANSDUCER SYSTEM AND CARTRlDGE THEREFOR [75] Inventor: MarvinCamras, Glencoe, Ill.

[73] Assignee: lTT Research Institute, Chicago, Ill. [22] Filed: Aug.21, 1972 [21] Appl. No.: 282,275

52 use: 360/93, 242/5519 A, 242/75, 242/197, 360/130 51 1lnt.C1..G11b15/22, 01 1b 23/04, Gllb 15/29 58 Field ofSearch ..179/100.2z,100. 2226/59, 195; 242/75, 75.2, 75.5, 197, 187,

[56] References Cited UNITED STATES PATENTS 2,745,604 5/1956 Masterson242/75.5 3,154,308 9/1964 Faulkner 179/1002 2 3,265,817 8/1966 Gilman179/1002 Z 3,269,671 8/1966 Cole, Jr. 242/55.19 A 3,341,143 9/1967Nieland et al. 242/55.l9 A 3,370,131 Z/1968 Reed 179/1002 CA 3,388,9116/1968 Wilson et a1. 179/1002 CA 3,580,525 5/1971 Dopner 242/75 PrimaryExaminer-Alfred H. Eddleman Attorney, Agent, or Firm-Hi1l, Gross,Simpson, Van Santen, Steadman, Chiara & Simpson [5 7 ABSTRACT A videotape cartridge of endless loop configuration capable of tape speeds of120 inches persecond while providing one hour or more of continuousplaying time on A inch width tape. In an illustrative embodiment thetape drive is steady enough so that the reproduced signal can be coupledto the antenna circuit of a home television receiver withoutmodification of the conventional synchronizing circuits.

3 Claims, 32 Drawing Figures PATENTELHBVI 9W 3,849,197 SEEM IMF 8PATENTEL: NOV 1 91974 d9 79 7 VIDEO TRANSDUCER SYSTEM AND CARTRIDGETHEREFOR CROSS-REFERENCES TO RELATED APPLICATIONS As to the feature ofbraking of the capstan-flywheel assembly, reference is made pursuant to35 U.S.C. 120 to my applications U.S. Ser. No. 401,832 filed Oct. 6,1964 (now US. Pat. No. 3,495,046 issued Feb. 10, I970), Ser. No. 848,992filed Aug. 8, 1969 (now abandoned), and Ser. No. 199,977 filed Nov. 18,197i which continues the subject matter of my applications Ser. No.401,832 and Ser. No. 848,992.

SUMMARY OF THE INVENTION This invention relates to a cartridge typevideo transducer system, and to an endless loop magnetic tape cartridgefor use in such a system.

It is an object of the present invention to provide a cartridge typesystem wherein the tape is continuously scanned in only a singledirection by means of a nonrotating magnetic transducer head along atrack of much greater length than the length of the tape, and yetwherein the tape may be moved at video transducing speed for transducingvideo signals suitable for display on a conventional broadcasttelevision receiver.

A further object is to provide an endless loop cartridge and transporttherefor capable of providing record tape speeds as high as 120 inchesper second or more, if desired, with a desired low degree of tapeflutter at the transducer head.

Another object is to provide an endless loop transducer system capableof providing one hour or more of playing time in conjunction with aconventional broadcast television receiver, while utilizing only asingle non-rotating transducer head, and preferably with the use of agradual shifting of the head in the lateral direction in moving betweenlongitudinal tracks on the tape 7 to avoid any discontinuity in theplayback process.

A still further object of the invention is to provide a simple andeconomical cartridge type video transducing system having very fewmoving parts and compact configuration, and yet which provides anextremely steady tape motion at the transducing location.

Another object is to provide a tape transport including a capstan driveassembly for determining tape speed at a transducing location and forproviding a particularly stable scanning relationship between the tapeand the transducer head at such transducing location.

Another and further object of the invention is to provide a novelendless loop cartridge transducer system wherein a precision typecapstan drive assembly is engagable and disengagable with the taperecord medium without the necessity for manual threading of the recordtape.

A subsidiary object of the invention is to provide such an endless loopcartridge transducer system wherein the operating tape path is free ofsharp bends and yet wherein the transducer system accommodates anextremely compact cartridge configuration.

An important feature of the invention resides in the provision of acapstan drive assembly constructed for cooperation with a transducerhead having a convex tape engaging face for optimum head-to-tape contactwithout the necessity for critical adjustment or excessive wear.

A further feature of the present invention resides in the provision of amagnetic transducer head especially suited for video signals and capableof operating with relatively high alternating current bias frequenciessuch as 10 megahertz or more.

Another feature resides in the provision of a longitudinal scanning typevideo transducer system capable of transducing television signals atrelatively low tape speeds of the order of 30 inches per second.

A further feature of the invention relates to a continuous loopcartridge machine capable of transducing at least 40 channels on aquarter inch wide record tape without substantial cross talk betweenchannels.

Additional important objects and features of the invention reside in atape transport for use in transducing any desired type of signal(including audio, instrumentation and data signals) giving exceptionalsteadiness of drive motion; in a cartridge of a construction whereby acapstan and multiple pressure rollers and the transducer head enter theinterior during operation; and/or in a tape drive wherean isolatedscanned portion of the record tape is slidably supported closelyadjacent the capstan along both sides of its path between capstan drivepoints.

Further features relate to the provision of a maintenance-free driveusing no belts or pulleys; and/or a capstan drive with a tape engagingface that exposes the tape to a head so that the head is freely movablebetween successive longitudinal channels from one edge of the tape tothe other.

Still other objects and features relate to a cartridge adapted forcoupling to a stable drive system; having no rotating parts except atape turntable; and/or requiring no rollers or precise parts that affectthe drive accuracy.

Other objects, features and advantages of the invention will be readilyapparent from the following description of certain preferred embodimentsthereof, taken in conjunction with the accompanying drawings althoughvariations and modifications may be effected without departing from thespirit and scope of the novel concepts of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial somewhatdiagrammatic plan view of a tape transport for an endless loop tapecartridge transducer system in accordance with the present invention;

FIG. 2 is a somewhat diagrammatic plan view on a reduced scale of anendless loop cartridge for association with the tape transport of FIG.1, with the top cover of the cartridge removed to reveal the internalconstruction;

FIG. 3 is a somewhat diagrammatic plan view on the same scale as FIG. 2showing the tape transport of FIG. I having the cartridge of FIG. 2associated therewith and showing the transport mechanism in theoperating condition;

FIG. 4 is a somewhat diagrammatic top plan view of the crescent guideelement of the transport of FIG. 1 and showing the crescent guide at itsfull size;

FIG. 5 is a somewhat diagrammatic front elevational view of the crescentguide element of FIG. 4;

FIG. 6 (on sheet 3 of the drawings) is a somewhat diagrammatic viewillustrating the internal operating parts of the transport in theloading position thereof;

FIG. 7 is a view on the same scale as FIG. 6, but showing the relativeposition of the parts in the operating condition of the transportmechanism;

FIG. 8 (on sheet 1 of the drawings) is a fragmentary side elevationalview of the tape transport of FIG. 1;

FIG. 9 (on sheet 1 of the drawings) is a vertical crosssectional viewshowing the capstan drive assembly of FIG. 8 in cross-section;

FIG. 10 (on sheet 1 of the drawings) is a somewhat diagrammaticperspective view showing a modified form of tape transport in accordancewith the present invention;

FIG. 11 is a partial somewhat diagrammatic side elevational view showinga head indexing mechanism suitable for the embodiment of FIG. 10;

FIG. 12 is a somewhat diagrammatic horizontal sectional view takengenerally along the line XII--XII of FIG. 11;

FIG. 13 is an enlarged partial vertical sectional view taken generallyalong the line XIII-XIII of FIG. 11, and showing further features ofpreferred head indexing mechanism, which features are not present in thehead indexing mechanism of FIG. 10;

FIG. 13A is a fragmentary vertical sectional view illustrating abidirectionally operative detent providing a releasable coupling in thehead indexing drive train;

FIG. 14 (on sheet of the drawings) is a somewhat diagrammatic plan viewof the cartridge receiving mechanism applicable to the embodiment ofFIG. 10, but with certain parts removed to show further details thereof;

FIG. 15 is a fragmentary somewhat diagrammatic plan view similar to thatof FIG. 14 but showing parts of the mechanism in the operating position;

FIG. 15A is a diagrammatic illustration of an electric circuit forcontrolling the gradual shifting of the head from one channel to thenext in response to a signal from a photocell or the like;

FIG. 16, (on sheet 4 of the drawings) is a somewhat diagrammaticfragmentary enlarged horizontal section view, with certain parts brokenaway and in section, to illustrate details of construction andillustrating a preferred capstan flywheel brake assembly specificallycorrelated with the cartridge receiving mechanism of FIGS. 14 and 15;

FIG. 17 is a somewhat diagrammatic partial vertical sectional view takengenerally along the line XVII-X- VII of FIG. 16;

FIG. 18 (on sheet 6 of the drawings) is a somewhat diagrammaticfragmentary perspective view showing a cover for sliding engagement withthe end of the cartridge of FIGS. 2 and 3, and applicable to any of theembodiments herein, for the purpose of completely enclosing the tapewhen not in use;

FIG. 19 is a somewhat diagrammatic perspective view showing a tapetransport generally corresponding to that of FIGS. -17 but with a coverenclosing the operating components of the transport mechanism such asthose shown in FIGS. 11-13, 14 and FIG. 20 is a partial plan view of thecover assembly of the machine of FIG. 19, looking into the cover asdetached from the remainder of the mechanism and inverted to reveal itsinternal parts;

FIG. 21 is somewhat diagrammatic transverse sectional view on adifferent scale and taken generally along the line XXI-XXI of FIG. 20;

FIG. 22 is a fragmentary enlarged longitudinal sectional view takengenerally along the line XXIIXXII in FIG. 20;

FIG. 23 is a somewhat diagrammatic enlarged fragmentary verticalsectional view illustrating details of a preferred record-play controlmechanism which is preferably associated with the cover of the machineof FIG. 19;

FIG. 21 is a somewhat diagrammatic partial horizontal sectional viewtaken generally along the line XXIV-XXIV of FIG. 23 and illustrating thecondition of the parts in the playback mode;

. FIG. 25 is a view similar to FIG. 23 but showing the condition of theparts in record mode;

FIG. 26 is a horizontal sectional view taken generally along the line ofXXVI-XXVI of FIG. 25;

FIG. 27 is a somewhat diagrammatic plan view of the cartridge of FIG. 2,with the top cover in place;

FIG. 28 is a vertical sectional view of the cartridge, taken generallyalong the line XXVIII-XXVIII of FIG. 27;

FIG. 29 is a horizontal sectional view, taken generally along the lineXXIX-XXIX of FIG. 28; and

FIG. 30 is a somewhat diagrammatic enlarged bottom plan view of a tapesupport subassembly removed from the cartridge, and showing the tapeguide arms at an extreme position beyond that permitted when thesubassembly is mounted in the cartridge.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring to FIG. 1 there isillustrated a tape transport 10 for removably receiving an endless looptape cartridge such as indicated at 11 in FIG. 2 on sheet 2 of thedrawings. The tape transport includes a support 12 for removablyreceiving the endless loop cartridge 11 and a capstan drive assembly 14for driving the tape of the cartridge at video transducing speed duringa transducing operation. The support 12 carries suitable cartridgepositioning elements such as lugs indicated at 15 and 16 in the FIG. 3for engaging in cooperating recesses of the cartridge to provide for apivotal type of movement of the cartridge on the lugs as the cartridgeis loaded onto the support 12. By way of example, the support 12 mayfurther include elements 19 and 20 as indicated in FIG. 3 for laterallyconfining the cartridge 11 while accommodating pivotal movement of thecartridge from an inclined position to the operative position. As thecartridge is pivoted downwardly, the length of tape indicated at 25 inFIG. 2 is automatically threaded between the capstan drive assembly 14and the retracted capstan pressure rollers indicated at 26 and 27 inFIG. 1. As the cartridge moves downwardly, I

a photocell assembly 28 on the cartridge support 12 moves through anaperture 29, FIG. 2, in the bottom of the cartridge so as to be disposedin operative relationship to the path of the tape carried by thecartridge.

The lugs 15 and 16 are mounted on flat pads 30 and 31 having a commonlevel with pads 32 and 33, FIG. 1, so as to position the cartridge at apredetermined level on the support 12. Spring fingers 34 and 35 projectupwardly from support 12 as indicated for finger 35 in FIG. 8 and serveto retain the cartridge securely in position. The lugs 15 and 16 includeforwardly projecting fingers 15a and 16a which overlie a Referring toFIG. 1 transducer head 40 is mounted on the transport for shiftingmovement toward and away from the capstan drive assembly 14. Further,the head assembly is capable. of indexing movement parallel to the axisof the capstan drive assembly so as to scan along successive parallelchannels extending lengthwise of the tape. The mechanism for indexingthe head 40 includes a solenoid 41 having an actuating link 42 forsuccessively indexing ratchet wheel 43 in cooperation with tensionspring 44 and pawl 45. For the sake of diagrammatic illustration, FIGS.1 and 3 show an arm 46 pivotally mounted near its center on pin'47, thearm being located so as to carry pawl 45 at its upper end and so as toconnect with link 42 and spring 44 at its lower end. Retraction of link42 towards the left by energization of solenoid 41 pivots arm 46 towardsthe right so as to advance pawl 45. When the solenoid is deenergized thelink 42 is restored by the pull of spring 44 to the position shown inFIG. 3. Thus pawl 45 is retracted while detent 48 locks ratchet wheel 43against reverse rotation. The pawl 45 is spring urged in thecounterclockwise direction as is detern 48, so that the manual knob (notshown) corresponding to knob 341, FIG. 10, may rotate ratchet wheel 44in the counterclockwise direction to manually select any desiredindexing position of the head. The parts associated with ratchet wheel44 may include the parts driven by member 360, FIG. 13, so that the knobon shaft 49 in FIG. 3 may drive such parts (just as knob 418 drivesparts 360 and 371 in FIG. 13) when the solenoid 41 is inactive. By wayof example ratchet wheel 43 may have 40 teeth corresponding to 40successive scanning positions of the head assembly 40. In thearrangement of FIG. 1, the indexing wheel 43 and the actuatingcomponents such as 41, 42, and 44-49 are all reciprocally movable withthe head 40 toward and away from the capstan drive assembly 14.

On the other hand, capstan pressure rollers 26 and 27 are mounted bymeans of stationary pivot shafts 51 and 52, the rollers being carried bylinkage arms 54, 55 and 56, 57 which are actuated so as to move towardthe capstan drive assembly 14 along with the head 40. The linkage armsare actuated by means of cam arms such as indicated at 61 in FIG. 1 andat 61 and 62 in FIGS.

'3 and 6 which have fixed pivot points 63 and 64 and which have rollers65 and 66 riding in recesses provided between interior sidewalls ofbrackets 67 and 68, and the adjacent sides of arms 54 and 56, for thepurpose of shifting the arms 54 and 56 from the positions shown in FIG.1 to the positions shown in FIG. 3 as the head 40 is moved to thetransducing position. A shiftable carrier including a slide plateindicated at 70, FIGS. 1 and 6, carries the head assembly 40 and theassociated indexing mechanism and also carries actuating pins as shownat 71 and 71a in FIG. 7, for pivoting the cam arms 61 and 62.

As will be explained hereinafter in greater detail, the plate 70 alsocarries a'pin 91, FIGS. 6 and 7, for controlling a reel brake 92, FIGS.3, 6 and 7, and carries a cam post 93 for controlling a tape dragelement 94 which is pivoted at 95, and which drag element carries a feltpad 94a for pressing the tape against a fixed guide 96. Reel brake 92and drag element 94 which is pivoted at 95, and which drag elementcarries a felt pad 94a for pressing the tape against a fixed guide 96.Reel brake 92 and drag element 94 are contained in the cartridge,through the latter could be part of the machine.

Preferably, the photocell assembly 28 which projects into the tapecartridge carries at its lateral face 93 a photocell exciting lamp, anda receiving photocell which is actuated in response to a lightreflective strip (not shown) applied to the tape when such strip reachesthe tape run as indicated at 99 in FIG. 3. In the absence of thereflective strip, the tape at path section 99 does not reflectsufficient light to the photocell to actuate the photocell circuit. Thephotocell circuit in turn controls actuation of the solenoid 41 so thatthe head 40 is indexed to scan a new channel each time the reflectivestrip reaches the photocell assembly 28.

Additionally the tape transport 10 carries an actuating arm as indicatedat 101 which is secured for actuating a vertical shaft 102 which in turnserves to control a flywheel brake assembly 103, FIG. 8. Pin 104, FIG.3, on the shiftable carriage is so located that as soon as drivingengagement between the tape and the capstan drive assembly is released,arm 101 is actuated to apply the brake 103. The details of a preferredcapstan flywheel brake will be described hereinafter in reference to asecond embodiment of the present invention. The pivot arms and 111carried on carriage plate 70, FIGS. 6 and 7, provide guide faces 110aand 11 la for engagement with lower portions of the arms 55 and 57(below rollers 26 and 27) as the carriage is advanced to operatingposition. Wire springs 112 and 113, FIG. 6, are actuated by arms 61 and62 as the wire springs advance with the carriage to urge arm 110counterclockwise and arm 11] clockwise. Arms 110 and 111 in turn act onarms 55 and 57 so as to establish pressure engagement between thecapstan rollers 26 and 27, and the capstan drive 14. The extent ofpivotal movement of arms 61 and 62 is selected so as to move thelinkages 54 and 55 and 56 and 57 into the proper position before thewire springs 112 and 113 become effective.

As the side plate 70 moves to the operating position, its right-handedge as viewed in FIG. 1, actuates a microswitch actuating arm 118 whichserves to actuate a microswitch controlling the energizing circuit forcapstan motor 119, FIG. 9, so as to begin driving the tape past head 40.Similarly the capstan motor is deenergized by virtue of a spring actingon arm 118, as the carriage plate 70 is returned to the load positionshown in FIG. 1.

The capstan drive rollers preferably have the configuration shown in theseventh figure of my copending application'Ser. No. 60,806 for thepurpose of establishing a substantial tension in the tape loop beingscanned by the transducer head 40. The groove in capstan roller 27 iswider than the tape and may have a depth of 0.0015 inch, so that thetape engaging diameter of roller 27 is 0.003 inch less than thatofroller 26.

Referring to FIGS. 2 and 3 on sheet 2 of the drawings, the cartridge 11includes a reel 120 mounted for rotation on a central bearing withminimum friction. By way of example, the base plate 122 of the cartridgemay have an upstanding bearing post as indicated at 123, and a bearingball 124 may be interposed between the flat upper face of the bearingpost 123, and a conically shaped seat carried by hub portion 125 of reel120, so

that reel 120 is supported by means of the ball 124 for relatively freerotation on the post 123. An axially elongated sleeve of hub portion 125closely receives post 123 to maintain the reel in a horizontal conditionwhile freely accommodating rotation thereof. The hub 125 of the reel 120is made as light as possible consistent with structural rigidity andincludes a central annular portion and an outer hub portion joined bythin radial arms such as indicated at 126. A lower radial flange 127extends from the lower side of the hub 125 and mounts a coil 128 ofrecord tape wound on the hub 125. The inner end of the coil 128 extendsover a contoured guide surface 130 formed of a low friction material.The tape engaging portion of the guide 130 is contoured so as to requirea minimum distortion in the natural tape path from the inner side ofcoil 123 to the path between the tape drag elements 94 and 96. The tapeafter passing between the drag elements 94 and 96 passes about guidepins carried at the free ends of arms 132 and 133 which have fixed pivotpoints at 95 and 135, respectively. A bias spring (not shown) urges thearms 132 and 133 counterclockwise and clockwise respectively so as tomaintain the tape adjacent the wall portions 137 and 138 of thecartridge and thus retain the tape section 25 in a relatively tautcondition. From the pin of pivotal guide arm 133, the tape passes abouta flanged guide post 140 and past aperture 29, and then about a flangedpin on tensioning arm 143 which is pivotally mounted at 144. From pivotshaft 144, the tape returns and is wound on the outer side of coil 128.A tension spring is indicated at 150 for urging a drag arm 151 in thecounterclockwise direction about pivot point 95 so as to urge themovable drag element 94 toward the fixed drag element 96.

Referring to FIG. 2, the spring bias on arms 132 and 133 suppliessufficient tensioning action to the tape so that the tensioning arm 143is held so as to place its spring under substantial torsion and thusmaintain the free loop under tension. The reel 120 is held against rotation by means of the reel brake 92.

Cam post 93, FIG. 1, has a cam face which cooperates with a flange 152,FIG. 7, depending from arm I51, so as to release the clamp ofdragelement 94 when the cartridge is loaded onto the tape transport ofFIG. 1. The flange 152 on arm 151 is so arranged as to maintain the drag94 in released condition until the head carriage reaches approximately90 percent of its travel toward the engaged position shown in FIG. 3.The arm 151 is then released so as to allow the tension spring 150 toapply drag force on the tape between elements 94 and 96.Correspondingly, when the head carriage is retracted, the drag forceexerted by elements 94 and 96 is released substantiallycontemporaneously with the release of driving pressure between the tapeand the capstan drive assembly 14. When the capstan stops driving, thetakeup tension of the tape as it winds on to the outside of the coastingreel 120 is too low to overcome the drag of elements 94 and 96.Consequently if the drag at elements 94, 96 were not released, therotation of the reel would supply a slack tape loop in advance of thedrag elements 94 and 96 until such time as the coil 128 became too tightto permit further rotation of the reel. The slack loop might jam, whilethe tightened coil might disturb subsequent normal operation.

To stop the coasting reel smoothly and quickly a leather brake shoe 92is carried on an arm 153 which is pivoted on axis 154 against the actionof a wire spring 155 by means of the pin 91, FIGS. 1 and 7, as theearriage is advanced to the operating position.

It will, of course, be noted that the bottom wall 122 of the cartridgeis provided with an aperture as generally indicated at 156, FIG. 2, soas to receive the capstan drive assembly 14 within the tape loop 25 asthe cartridge is loaded onto the transport 10.

In the engaged position of the transport as indicated in FIG. 3, wiresprings 112 and 113, FIG. 7, serve to urge the capstan pressure rollers26 and 27 against the capstan so as to establish an isolated tape loopextending from an incoming side of the capstan drive to an outgoing sideof the capstan drive, the drag elements 94 and 96 acting on an incomingtape path section such as indicated at 164, FIG. 3, and an outgoing tapepath section such as indicated at 165 having essentially zero tension,but being sufficiently guided so as to pass in close proximity to thephotocell assembly 28 which carries the lamp and photocell previouslyreferred to. It will be noted that throughout the incoming tape path 164from the inner side of coil 128 to the incoming side of the capstandrive assembly, the tape follows a path having a total amount of bendingof substantially less than and in fact less than 45, so as to enable arelatively free movement of tape. If the tape had a relativelysubstantial bend at the incoming path section, this would tend toamplify any flutter which might occur along the incoming path section.The tape drag elements 94 and 96 apply a relatively substantial dragforce which in conjunction with the capstan drive assembly provides atape tension at the transducer head 40 in a range from about one to fourounces for a A inch tape.

The space between the level of the flange 127 of reel and the bottomwall 122 is appreciably less than the width of the tape, for examplel/l6 inch. The reel 120 might be one half to two thirds full where thelength of tape was to provide 40 channels with a capacity of 1 hour ofplaying time at 120 inches per second. The constant friction supplied bythe drag elements 94, 96 tends to swamp out any irregularities in tapemotion, for example due to variations in thefriction exerted by the coil128 as the tape is unwound from the inner side thereof, and is importantin proper guiding of the tape over the pressure rolls, capstan, andhead.

As seen in FIG. 3, the flywheel brake operating arm 101 assumes aposition adjacent its actuating pin 104 so that the brake is applied tothe capstan flywheel as soon as the capstan drive is released byretraction of the capstan pressure rollers 26 and 27. The tape remainssomewhat loosely at the capstan when the rollers are retracted, butre-engages perfectly if the rollers are brought again to drive position.The tape section 25 is brought to the taut condition shown in FIG. 2when the cartridge is removed from the machine and the arms 132 and 133return to the loading positions as shown in FIG. 2 under the impetus oftheir spring bias.

The mechanism for shifting the arms 132 and 133 to the operatingposition as the cartridge is loaded on the machine will be explained inconnection with FIGS. 27-30. Briefly, however, the machine carriesactuating rollers 17] and 172, FIG. 1, which engage inclined edges ofslide plates 173 and 174, FIG. 2, as the cartridge is pivoted into theoperating position. As the cartridge is pressed downwardly into theoperating position, the rollers 171 and 172 force the slide plates 173and 174 laterally against the action'of spring bias. A suitable lostmotion type linkage couples the slide plates 173 and 174 with the pivotshafts 95 and 135, causing arm 132 to rotate in the clockwise direction,and causing arm 133 to rotate in the counterclockwise direction untilthe arms reach the operating positions as shown in FIG. 3. (The arm 151is freely rotatable relative to the pivot shaft 95, the pivotal movementof the arm 151 relative to shaft 95 having been previously explained.)

FIGS. 8 and 9 (on sheet one of the drawings) illustrate a preferredcapstan-head arrangement generally corresponding to that illustrated inthe prior Camras applications Ser. No. 44,510 filed June 8, 1970, andSer. No. 60,806 filed Aug. 4, 1970. The capstan drive I assembly 14includes a tape guide 200 providing sliding support for the tape as ittravels along the loop path between the incoming and outgoing sides ofthe capstan. As best seen in FIGS. 4 and (on sheet 2 of the drawings),the tape guide 200 is provided with a tape guide channel 201 whichextends across a vertically extending recess 202. As seen in FIG. 4, therecess 202 has a generally concave configuration in cross section whichis adapted to accomodate the generally convex tape engaging face 203,FIG. 1, of the head assembly 40. As

best seen in FIG. 5, the tape channel 201 is defined by tape engagingguide surfaces 205 and 206, having a crowned or bulging configuration(shown exaggerated), so that the tape has a slight lateral curvature incross-section over the extent of the tape channel 201 except in thevicinity or the recess 202. At the transducing region of the tape pathwhere the tape spans recess 202 and is engaged by the transducer head40, the tape may have a substantially flat or rectangular cross sectionconfiguration, or even have an opposite lateral curvature, if the head40 has a crowned configuration such as illustrated in the first figureof the copending application Ser. No. 90,773 filed Nov. 18, 1970. Thestationary tape guide surfaces 205 and 206 are of generally arcuateconfiguration, conforming to the configuration of the outer edges ofsections 207 and 208 of the guide 200 as illustrated in FIG. 4. The tapeguide surfaces 205 and 206 are of a length in the direction of movementof the record tape so as to provide sliding support for the record tapeloop over substantially the entire length thereof which is out ofengagement with the capstan. With the head 40 in the operating position,the tape is also provided with sliding support at the tape engagingsurfaces 203 of the head.

The tape guide 200 further comprises a magnetic shielding member asindicated at 210 in FIG. 4 which is interposed between the capstan drivesleeve 212, FIG. 9, and the record tape loop which extends along theguide channel 201, FIG. 5. The magnetic shielding member 210 may beformed ofa thin sheet of magnetic material disposed in close conformingrelation to the tape engaging surface 212a of the capstan sleeve 212,while being slightly spaced therefrom to accommodate free rotation ofthe capstan. By way of example the magnetic shielding member may be madeof Permalloy" having a composition of 4 percent molybdenum, 78 percentnickel. and the remainder iron and minor constituents. The remainder ofthe tape guide 200 may be of thin electrically conductive material suchas bronze with a hard chrome plating on its wearing surfaces. Crownedguide channels 201 were found advantageous in guiding the tape with aminimum of tension.

Optimum crowing of about 1.5 inch radius gave the steadiest picture foran embodiment in accordance with FIGS. l-9, but with very light tapedrag. As seen in FIG. 9, base 214 of the tape guide 200 may be fixedlysecured to housing 215 of the capstan drive assembly 14.

As best seen in Flg. 9, in a preferred arrangement, a capstan shaft 220has capstan sleeve 212 rigidly fixed or integral therewith and has aflywheel 221 rigidly fixed on the shaft 220. The sleeve is bronze, brassor similar non-magnetic material with a surface of hard chrome. Theshaft 220 is preferably of hard magnetic steel. The non-magnetic capstansleeve and surface prevents spurious pickup from the magnetic shaft bythe nearby head which is very sensitive to even the slightestmagnetization of a close spaced capstan.

With a head-adjacent-capstan configuration, a nonmagnetic stainlesssteel shaft was found to have poor bearing qualities and further evenwhen carefully demagnetized still had sufficient permanent magnetizationto introduce undesirable noise levels into the head winding. Othernonmagnetic materials which might be used have poor bearing qualitiesparticularly at high speeds such as 3,600 rpm. A reduced diameterportion 222 of the rotor shaft is journalled in an upper bearing 223which is supported by a rigid frame portion 224 which may be an integralpart of the capstan housing 215. The casing 226 of the capstan drivemotor 119 is rigidly secured with the housing 215. The rotor of themotor 119 is directly secured to capstan shaft 220, and the shaft isjournalled by means of a bearing 227 below the rotor. With thisarrangement, a much steadier capstan motion is insured. Because of thesteady motion thus achieved, the output from this magnetic head assembly40 can be supplied directly to a conventional television receiverwithout the need for special flutter compensation circuits, inaccordance with the illustration in the second figure of my copendingapplication Ser. No. 60,806. As explained in this copending application,capstan shaft 220 may have a diameter corresponding to the outsidediameter of sleeve 212 to itself provide the capstan drive surface 212a.An exhaust impeller blade is indicated at 230 for rotation with thecapstan shaft 220 to exhaust air from the housing 215 through aperturessuch as indicated at 231. Suitable air intake apertures may be providedat the lower end of the casing of motor 226 below stator 240 as viewedin FIG. 9. In addition to sleeve type bearing 227 at the lower end ofthe shaft 220, a thrust bearing in the form of a ball 241 is shown inFIG. 9. The capstan-flywheelrotor component including shaft 220, sleeve212, flywheel 221 impeller 230 and rotor 242 is dynamically balancedsuch that vibration and noise is reduced to a negligible amount.

Referring to FIG. 8, it will be observed that the capstan brake 103 isreciprocally guided by means of a fixed casing 250 secured by means ofscrews such as indicated at 251 to the capstan housing 215. A tensionspring is indicated at 252 which in one embodiment in accordance withFIGS. 1-9 serve to release the capstan brake 103 upon disengagement ofthe pin 104 from the arm 101, FIG. 3, as the carriage plate moves to theoperating position shown in FIG. 3. In this embodiment. as the carriageplate is retracted, pin 104 engages arm 102, and rotation of arm 102drives plunger 103, FIG. 8, inwardly so that the brake shoe of the innerend of the plunger 103 engages the periphery 221a of the I flywheel 221,FIG. 9, with the desired braking pressure. In a preferred embodiment,the parts are rearranged so that the spring serves to apply the brakingpressure as the slide plate is retracted toward the loading position. Inthis preferred embodiment, a pin on the carriage plate 70 serves torelease the brake as the carriage plate is moved from the loadingposition, the flywheel brake being maintained in the disengagedcondition by the pin with the parts in the operating position as shownin FIG. 3. The details of a preferred flywheel brake arrangement aredescribed in connection with a second embodiment of the presentinvention to be described hereinafter.

It may be noted that FIG. 1 is based on a photograph of an actualembodiment, the photograph having been taken at a slight angle to thevertical, so that the parts in FIG. 1 are seen in some portions with aslight degree of parallax.

EMBODIMENT OF FIGS. -18

Referring to FIGS. 10-18, a preferred embodiment of the presentinvention is illustrated wherein capstan drive assembly 301 essentiallycorresponds to the capstan drive assembly 14, FIG. 1, and includes acapstanmotor-flywheel assembly such as illustrated in FIG. 9, andincludes a tape guide in association therewith corresponding to thatillustrated in FIGS. 4 and 5. The embodiment of FIGS. 10-18 includes acartridge support 302 essentially corresponding to that indicated inFIG. 1 including a photocell assembly 303, FIG. 14, corresponding tothat shown at 28 in FIGS. 1 and 3. Pivotal loading of the cartridge isaccommodated by elements 304-307 corresponding to elements 15, l6, l9and in FIG. 3. As in the previous embodiment, pads are provided at 309and 310 adjacent the retaining lugs 304 and 305, and pads 309 and 310are at the same level as pads 311 and 312 so as to provide level supportfor the cartridge. Spring fingers 313 and 314 are located at the forwardedges of pads 311 and 312 in a manner analogous to the placing of springfingers 34 and 35 in FIG. 1. Thus, as the cartridge is pivoteddownwardly into the operating position, spring fingers 313 and 314insure the interlocking of the cartridge with the overhanging fingers304a and 305a of lugs 304 and 305. A slide plate 317 is indicated inFIG. 10 which corresponds essentially to the slide plate 70 of FIG. 1,and includes a pin 318 sliding within an elongated slot 319 on the slideplate 317 is reciprocated from the loading position indicated in FIG. 14to the operating position shown in FIG. 15. Slide plate 317 is providedwith a cam edge 317a for actuating a microswitch arm 321 to startcapstan motor 322 as the slide plate 317 reaches the operating position.Capstan pressure rollers such as indicated at 323 correspond essentiallyto the capstan pressure rollers 26 and 27 and are mounted for pivotalmovement by means of linkage arms such as indicated at 324 and 325,FIGS. 14 and 15, and 326 and 327, FIG. 10, corresponding to the pivotarms 54, 55 and 56, 57 in FIG. 1. The arms 324 and 326 are mounted onfixed pivots 328 and 329, carried by the support 302 clear of the pathof movement of the slide plate 317.

A distinctive feature of the embodiment of FIGS. 10-18 resides in theuse of a motor energized head indexing movement whereby the headgradually moves from one channel to the next in such a way as to preventtransients during continuous playing of successive channels.Specifically, the drive for the head indexing mechanism includes a drivemotor 330, a reducing gear section 331, a control cam 332, spur gears333 and 334 and worm 335 which serves to drive a worm wheel mountedcoaxially with the head indexing mechanism 337.

Referring to FIG. 10, an enclosure may be provided for components suchas 330-335, and such enclosure may be threadedly secured to a post suchas indicated at 340 at each side of the transport. A manually operatedknob 341 may be attached to the remaining parts of the head indexingassembly 337, so that the knob 341 may be on the upper side of theenclosure and be coupled with the remaining parts of the head indexingmechanism lying within the enclosure. lndicia such as indicated at 342may cooperate with a suitable pointer and may be suitably numbered so asto represent the channel being scanned by the head assembly. Forexample, one index line may have associated therewith on the surface 343the numeral 35 indicating that when this index line is aligned with thepointer, the head assembly will be scanning channel number 35 on therecord tape.

Referring to FIGS. 11-13, details of a preferred head indexing assemblyare diagrammatically shown. This head indexing assembly is similar toassembly 337 in FIG. 10 but incorporates certain additional features.Spur gear 334 and worm 335 are shown in FIG. 12, and worm 335 has areduced shaft portion 335a which is visible at the lower left in FIG.11. The worm 335 drives a worm wheel 350, FIG. 13. The worm wheel 350 isprovided with a hub portion 351 secured by set screw 353 to a verticalshaft 352. A set screw 354 secures a ratchet tooth member 355 to shaft352 so that worm wheel 350 drives ratchet tooth member 355 having anannular series of ratchet teeth along an upper edge thereof as indicatedat 356. A ratchet follower sleeve 360 fits over shaft 352 and includes aratchet finger 361 for cooperating with the series of ratchet teeth 356.Specifically, rotation of the ratchet member 355 by means of the wormwheel 350 is effective to drive the member 360 therewith by virtue ofthe coupling between the ratchet finger 361 and the ratchet teeth 356.On the other hand, a knob 418 generally similar to knob 341, FIG. 10, istelescoped over a sleeve 370 of a cam member 371, so that the cam member371 may be directly rotated by means of the manual knob 418 withoutrotation of the worm 335. Specifically, as the knob 418 is rotated, theratchet finger 361 rides over the successive ratchet teeth 356, theratchet member 355 thus remaining stationary. On the other hand, as theworm 335 is driven, the cam member 371 and the indicator knob 418 areboth rotated therewith. Thus, the head indicated at 380, FIG. 12, may beadvanced automatically to successive channels by means of the motordrive, or the head may be set at any desired channel by manual operationof the knob 418.

The head 380 is carried by means of a bracket 381 which is guided forvertical reciprocation by means of a guide rod 383, and a guide grooveas indicated at 384. The head slide 387 includes an aperture slidablyreceiving guide rod 383 and includes a beveled edge 387a confined by theguide groove 384. The head slide 387 carries a cam follower 390 whichrides on the cam edge face 371a of cam member 371. The head slide 387 isshown in an intermediate position in FIG. 11 and is urged upwardly bymeans of the hairpin spring 393. As cam member 371 is rotated, camfollower 390 follows along the cam edge 371a to progressively depressthe head 380 against the action of the spring 393. When the head reachesthe lowermost position, further rotation of cam member 371 (in clockwisedirection as viewed in FIG. 12) causes the follower 390 to move beyondpoint 394 on the cam edge face 371a so that the head 380 is returned tothe upper position by action of spring 393; thus the head returns to thefirst channel and the indexing cycle is repeated. A bracket 395, FIGS.11 and 12, serves to fasten casing 396 of the head indexing mechanism toslide plate 317 as shown in FIGS. 14 and 15.

The casing has a journal member 397 secured therewith by screws 398, andthe journal member 397 together with spacer 399 accommodate rotation ofsleeve 360 while preventing any substantial axial movement thereof. FIG.12 shows a sectional view along lines XII- -XII of FIG. 11, but with cammember 371 removed from sleeve 360 to show underlying parts with greaterclarity.

In FIG. 11, the cam 371 is shown about one-quarter of a revolutionbeyond the position where the head is in scanning relation to the upperchannel (channel No. l) on the tape. Thus the head still has at leastabout 3/16 inch of downward travel from the position shown in FIG. 11before it reaches its lowest position, where the tape width is 54 inch.While slide 387 is shown approximately midway along the verticaI-extentof guide rod 383 in FIG. 11, nevertheless the dimensions shown in FIG.11 are such that slide 387 can still move downwardly the requireddistance of almost A inch.

FIG. 13A shows a modification of the head indexing drive train of FIG.13 wherein member 355' which is secured to shaft 352 as indicated formember 355 in FIG. 13, drives a follower sleeve 360' corresponding toratchet follower sleeve 360 in FIG. 13. In place of ratchet finger 361,sleeve 360 carries a spring urged detent ball 400 which coacts withsymmetrical detent teeth 356. The spring urged detent ball 400 actsagainst teeth 356' with sufficient force to insure that worm 350 willdrive cam member 371 in the same way as for the embodiment of FIG. 13.Knob 418, however, may be turned in either direction when thebidirectional detent of FIG. 13a is substituted for parts 355, 356, 360and 361 in FIG. 13.

FIGS. 16 and 17 illustrate details of a capstan flywheel brake similarto that indicated at 103, FIG. 8, and described in reference to theprevious embodiment. Thus, capstan motor 322 has a flywheel 401, FIG.16, thereon corresponding to the flywheel 221 shown in FIG. 9. Theflywheel housing 402 has a casing 403 secured therewith corresponding tocasing 250, FIG. 8. The casing 403 includes an interior wall 403a forreciprocally mounting a plunger 404 carrying brake shoe 405.

For actuating plunger 404, casing 403 is provided with a pivot shaft 406pivotally mounting a lever 407. The lever 407 has secured therewith acircular disk 408 which is rotatably journaled in a circular receivingap erture of casing 403. The lever 407 is fixedly secured with pivotdisk 408 by means of a screw as indicated at 410. Plunger 404 isprovided with an elongated aperture 404a receiving the pivot shaft 406therethrough so as to accommodate reciprocal movement of the plunger 404toward and away from the flywheel 401. The lever 407 is coupled withplunger 404 by means of a slot 408a disposed radially in the circularmember 408 and a pin 412 fixedly secured to plunger 404. Thus, as lever407 and disk 408 pivot about shaft 406, a radial wall of slot 408aengages pin 412. so as to drive the plunger 404 toward or away from theflywheel 401. A tension spring is diagrammatically indicated at 414which acts on the free end of lever 407 so as to tend to rotate thelever in the clockwise direction about shaft 406 as viewed in FIG. 16,so as to tend to establish pressure braking relation between brake shoe405, which may be of leather, and the periphery 401a of flywheel 401. Torelease the braking force on the flywheel 401, an actuating cam 415 isprovided in engagement with side edge 407a of lever 407, cam 415 beingrotatable with its shaft 416 in a clockwise direction to rotate lever407 in a counterclockwise direction about shaft 406 in retractingplunger 404 and brake shoe 405 away from the periphery 4010 of flywheel401. When the actuating cam 415 is released for rotation in thecounterclockwise direction back toward the position shown in FIG. 16,tension spring 414 serves to apply the brake to the flywheel.

Referring to FIGS. 14 and 15, actuating shaft 416 is shown as extendingthrough support 302 and carrying an actuating finger 420 disposed forengagement with an edge 3171) of slide plate 317 as the slide plate ismoved from the loading position shown in FIG. 14 to the operatingposition shown in FIG. 15. This movement serves to rock shaft 416 in theclockwise direction through a sufficient angle to release theapplication of brake 405 at the same time that microswitch arm 321 isoperated to start the capstan motor 322. On the other hand, as slideplate 317 is retracted from the operating position shown in FIG. 15,microswitch arm 321 is released to deenergize the capstan motor, andfinger 420 returns to its position in registration with notch 3170 so asto allow tension spring 414 to drive shaft 416 in the counterclockwisedirection while at the same time driving lever 407 in the clockwisedirection to apply brake 405 to the periphery 401a of flywheel 401.Thus, the capstan of the capstan drive assembly 301 is rapidly broughtto a stop as the slide plate 317 is retracted to the loading position.

FINE ADJUSTMENT FEATURE FOR THE HEAD INDEXING MECHANISM OF FIG. 13

The structure so far described with reference to FIGS. 11-13 may beconsidered as applied to the head indexing mechanism 337 of FIG. 10 aswell as to the head indexing mechanism of FIG. 13 which specificallyincorporates a fine adjustment feature. In particular, in the embodimentof FIG. 13, actuating knob 341 of FIG. 10 is replaced by a knob assembly417 including a main adjustment knob 418 whose operation correspondsexactly to the operation of knob 341 in FIG. 10. The knob assembly 417further includes a fine adjustment knob part 419 which in the embodimentof FIG. 13 is rotatable relative to the main knob part 418. Thus, ifknob parts 418 and 419 were fixedly secured together, the embodiment ofFIG. 13 would correspond essentially to the head indexing mechanism 337of FIG. 10. That is, knob parts 418 and 419 could be replaced by theknob 341 in FIG. 13, and the disclosure of FIGS. 11-13 would then beapplicable to the head indexing mechanism 337 shown in FIG. 10.

Referring to the fine adjustment feature of FIG. 13, it will first beobserved that end bearing washer 420 is fixedly secured to the end ofshaft 352 by means of screw 421 and serves to prevent axial displacementof fine adjustment knob 419 relative to shaft 352, while accommodatingrotation of the fine adjustment knob 419 on the central vertical axis ofthe indexing mechanism. The fine adjustment knob 419 is provided with acam follower protrusion 419a which is in engagement with a circular camface 370a of sleeve 370. The slope of the cam face 370a is such that onerevolution of knob 419 will shift sleeve 370 axially a distance of0.0062 inch corresponding to the center to center spacing betweenadjacent tracks on the record medium being scanned by head 380. Acompression spring is indicated at 422 for accommodating shifting ofsleeve 370 and cam part 371 relative to the adjustment knob 419 in theaxial or vertical direction. The sleeve 370 is provided with an internalkeyway 370b which is in alignment with a keyway 360a of ratchet followersleeve 360. A key is shown at 423 for locking members 360 and 370 forjoint rotation while accommodating the required slight axial movement ofmember 370 and main knob 418 relative to member 360. Main knob 418 issecured with the cam sleeve 370 by means of set screw 424.

The position of the fine adjustment knob 419 in FIG. 13 may representapproximately a mid point in its range of adjustment. Thus, if knob 419is rotated in the clockwise direction as viewed from the top, thefollower 419a will travel along an upwardly sloping part of cam face370a, forcing sleeve 370 and knob 418 downwardly against the action ofcompression spring 422. As cam part 371 integral with sleeve 370 isforced downwardly, edge face 371a of cam 371 will, of course, act on thefollower 390, FIGS. 11 and 12, moving the head slide 387 downwardlyagainst the action of wire spring 393. On the other hand, if the fineadjustment knob 419 is rotated in the counterclockwise direction,follower 419a will travel along a downwardly sloping portion of cam face370a, allowing spring 422 to raise sleeve 370 and knob 418, whereuponthe wire spring 393 will correspondingly raise the head 380, FIG. 12.There is, of course, sufficient friction provided by means of the spring422 so that the fine adjustment knob 419 will rotate with the main knob418 whenever the main knob is manually grasped at its knurled surface418a and rotated (in the clockwise direction) in indexing the headbetween successive channels manually. Since worm wheel 350 and ratchetmember 355 are locked against rotation as long as the motor 330 isdeenergized, main knob 418 can only be rotated in the clockwisedirection permitted by the ratchet finger 361. The ratcheting action offinger 361 relative to teeth 356 provides a manual feel" which enablesthe accurate manual indexing of the head to successive channels on thetape once the fine adjustment knob 419 has been accurately adjusted fora given tape. In any given position to which the knob 418 is rotated, aslight attempt to rotate knob 418 in the counterclockwise direction willinsure that ratchet finger 361 is tightly engaged with the correctratchet tooth 356 so as to establish the precise indexing positionduring manual channel selection.

As previously described, in the automatic mode of channel changing, thedeenergized positions of the motor 330 are accurately determined by thenotch 3320, FIG. 15A, of cam 332. The maximum variation in stoppingposition of the cam 332 is less than the angular extent of notch 332a.Since notch 332a may have an extent equal to about 36, for example, orabout 10 percent of the channel to channel separation, the possiblevariation may be less than 0.0006 inch or less than 10 percent of theadjustment range provided by fine ad- 5 justment knob 419. Further inactual operation the stopping position of the motor 330 is consistent towithin a degree or so, and as noted even the worst case of possiblevariation corresponds to less than 0.6 mil, a variation which would notbe noticeable in the picture produced by the head.

Preferably fine adjustment knob 419 has an established neutral positionto which it is set for recording operation such as the mid position inits range of adjustment. A detent is shown in FIG. 13 for acting betweenknobs 418 and 419 to establish the desired neutral position. Morespecifically adjustment knob 419 is shown as having a spring urgeddetent ball 425, and knob 418 is shown as having a ball receivingdepression 426 which serves to provide a manually discernible neutralposition of knob 419 relative to knob 418.

The manner in which the pressure rollers such as 323 are actuatedbetween the retracted position as shown in FIG. 14 and the operatingposition as shown in FIG. 15 can be understood from FIGS. 14 and 15,particularly when considered in conjunction with FIGS. 6 and 7 showingthe previous embodiment which is essentially similar. To assist incorrelating the showing of FIGS. 14 and 15 with the previousdiagrammatic showing of FIGS. 6 and 7, the last two digits of thereference numerals applied to the actuating components for the pressurerollers in FIGS. 14 and 15 will correspond to the digits of thereference numerals designating such parts in FIGS. 6 and 7. Inparticular, cam arms 461 and 462 in FIGS. 14 and 15 are actuated bymeans of pins such as indicated at 471a carried by the shiftable plate317 in a manner which is analogous to the operation of components 61,62, 71 and 71a in FIGS. 6 and 7. Pivot points for the cam arms 461 and462 are shown at 463 and 464 in FIG. 15. Further, a bracket isdiagrammatically indicated at 467 in FIGS. 14 and 15 fixedly secured tolinkage arm 324 and corresponding to bracket 67 in FIGS. 6 and 7. Asdiagrammatically indicated in FIGS. 14 and 15, cam arm 461 carries aroller 465 at the free end thereof, which roller corresponds to roller65 in FIGS. 6 and 7 and is confined between a side wall 467a of bracket467 and an edge of linkage arm 324 so that as arm 461 is actuated in theclockwise direction by movement of slide plate 317 to operatingposition, arm 324 is swung in a counterclockwise direction about itspivot 328 so as to occupy the position shown in FIG. 15. Similarly aroller 466 is mounted on the free end of cam arm 462 corresponding tothe roller 66 in FIGS. 6 and 7. In FIGS. 14 and 15, linkage arms 326 and327 and the pressure roller carried by arm 327 have been omitted so asto show the cooperation between arm 462 and other parts of themechanism. In particular pivot arms 510 and 511 are shown in FIGS. 14and 15 pivotally mounted on the slide plate 317 by means of pins 508 and509, these pivot arms corresponding to pivot arms and 111 in FIGS. 6 and7. The pivot arms are provided with guide faces 510a and 511a forengagement with portions of the linkage arms 325 and 327 located belowthe respective pressure rollers such as 323. Wire springs 512 and 513correspond to wire springs 112 and 113 in FIGS. 6 and 7, and arearranged so as to be actuated by the arms 461 and 462 at portionsthereofjust below the respective rollers 465 and 466 as specificallyshown for the arm 462 and spring 513 in FIG. 15. Thus, as the carriageplate 317 is advanced to the operating position, pins such as 471a coactwith cam surfaces such as 462a of cam arm 462 to pivot the cam arm 462counterclockwise on its pivot 464. This, of course, moves the associatedlinkage arm 326 in a clockwise direction about its pivot 329, FIG. 10,in a manner analogous to the movement of linkage arm 324 in thecounterclockwise direction about its pivot 328. As the linkage arms 324and 326 are moved in the counterclockwise and clockwise directionsrespectively about their pivots 328 and 329, the portions of arms 325and 327 coaxial with the pressure rollers ride on the guide faces 510aand 511a, FIG. 14, so as to cause the linkage arms 325 and 327 to pivotclockwise and counterclockwise respectively relative to the linkage arms324 and 326. As the pressure rollers such as 323 approach the operatingpositions such as that indicated for roller 323 in FIG. 15, arms 461 and462 begin exerting inward pressure on the respective wire springs 512and 513 so as to tend to rotate pivot arm 510 in a counterclockwisedirection about its pivot 508 and to tend to pivot arm 511 in aclockwise direction about its pivot 509, so that the pressure rollerssuch as 323 are pressed toward the capstan of capstan assembly 301 withthe correct degree of pressure.

Conversely, as slide plate 317 is retracted from the operating positionshown in FIG. 15, pins such as 471a are retracted so as to ride alongthe cam surfaces such as indicated at 462a, FIG. 14, the wire springs512 and 513 tending to urge the cam arms 461 and 462 in thecounterclockwise and clockwise directions respectively as permitted bythe pins such .as 471a. The cam arms 461 and 462 are also urged towardtheir initial positions shown in FIG. 14 because of torsion coil springs(not shown) acting on the linkage arms 324 and 326. For example, thetorsion spring acting on arm 324 has one end secured to base 602adjacent pivot shaft 328 and the other end attached to arm 324, thespring being loaded so that it urges arm 324 to rotate in a clockwisedirection about pivot 328. The other torsion spring associated with arm326 is similarly arranged and is loaded so as to urge arm 326 to rotatein a counterclockwise direction. In FIGS. 1, 6 and 7, wire springs 516and 517 are mounted on slide plate 70 so as to engage arms 54 and 56 asthe slide plate is retracted from the operating position shown in FIG.7, so as to rotate arms 54 and 56 from the position shown in FIG. 7 tothe position shown in FIG. 6. The springs 516 and 517 are thus analternative to the torsion coil springs actually used in FIGS. 10-17.

Wire springs such as that indicated at 521, FIGS. 14 and 15, act onlinkage-arms 324-327 in such a way that the linkage arms 324-327 assumethe collapsed configurations such as shown in FIG. 14 as slide plate 317is retracted to the loading position. These wire springs such as 521also insure that the pressure rollers such as 323 will be properlyguided by'means ofthe guide faces such as 510a as the slide is moved tothe operating position. Similar wire springs are shown at 518 and 519 inFIGS. 1 and 3.

As indicated for the linkage arm 324 in FIGS. 14 and I5, linkage arms324 and 326 may be provided with flange strips such as indicated at 525.(Arms 324 and 326 are shown in FIG. 10 without flange strips, as in anearlier version of the present embodiment.) These flange strips serve tooverlie the front edge of the cartridge in the operating position of themechanism as shown in FIG. 15 so as to prevent any attempt to remove thecartridge prior to returning'the mechanism to the load condition shownin FIG. '14.

CARTRIDGE FEATURE-FIG. 18

FIG. 18 (on sheet 6 of the drawings) shows the cartridge for theembodiment of FIGS. 10-17, the cartridge being designated by thereference numeral 11 since it is identical to the cartridge of FIG. 2.As explained in reference to the embodiment of FIGS. 1-9, the cartridgeis provided with an aperture 29 for receiving the photocell 28 and anaperture 156 therein which serves to receive capstan drive assembly 301,as the cartridge is pivoted downwardly into the operating position afterengagement with lugs 304 and 305, FIG. 14. The aperture 156 is furtherof a size to receive the capstan pressure rollers such as 323 which areadvanced as indicated in FIG. 15 into the aperture 156 as slide 317moves to the operating position. In the operating position, the stripssuch as indicated at 525 carried on the linkage arms 324 and 327 overlieregions such as indicated at 530 and 531 of cartridge 11 to prevent anyattempt at removing the cartridge 11 from the machine so long as themachine remains in the operating position as shown in FIG. 15. When,however, slide plate 317 is retracted to the loading position, thestrips such as 525 are pivoted about the pivot axes 328 and 329respectively to positions such as shown in FIG. 14 where the strips areentirely clear of the cartridge 11 and of the tape path indicated at 25at the front of the cartridge.

Once the cartridge 11 has been removed from the machine, a suitablecover such as indicated at 532 in FIG. 18 may be slipped over the frontend of the cartridge so as to completely cover any apertures thereinsuch as 29 and 156, FIG. 2, and thus render the cartridge dust proof andfully protect the tape at path section 25 of the cartridge. By way ofexample, the interior walls forming the left and right sides and top andbottom of the open space within the cover 532 may engage thecorresponding faces of cartridge 11 such that the cover 532 isfrictionally retained in assembly with the cartridge 11 against anyinadvertent separation, but the frictional retaining forces being suchthat the cover 532 can be readily manually removed from the end of thecartridge 11 when it is desired to mount the cartridge in the machine.Thus, the open end 533 of cover 532 provides an opening with across-section so as to relatively freely accommodate insertion of theend of cartridge 11. The edges of the cartridge such as indicated at 534and 535 may be sufficiently rounded so as to facilitate insertion of theend of the cartridge into the opening 533. The top and bottom andsidewalls of cover 532 and end wall 536 are completely solid and free ofapertures therethrough so as to provide an effective dust cover for thecartridge 11, which encloses and seals apertures 29 and 156, FIG. 2. Thetop and bottom edges of the cartridge 11 may also be sufficientlyrounded so as to facilitate insertion of the cartridge into the open end533 of the cover 532.

SUMMARY OF OPERATION (FIGS. 1-18) Except as specifically mentionedherein, the structure and operation of the embodiment of FIGS. l-9corresponds to the structure and operation of the embodiment of FIGS.10-18. The descriptionandiillustration of each embodiment isspecifically applied with respect to the other embodiment except wheredifferences are specifically noted or illustrated in the drawings. Thefollowing summary of operation will encompass both embodiments since thedetailed showings of various features of the respective embodimentscomplement each other in providing a complete understanding of both.

The cartridge for both embodiments is illustrated in FIG. 2 and is soconstructed that when removed from the transducer mechanism, a brake asindicated at 92 is applied to reel 120. Further, arms 132 and 133 arespring urged to the positions shown in FIG. 2 so as to define a straighttape path at 25 facilitating loading of the cartridge with the transportmechanism. A tape tension arm 143 is provided along the tape path forapplying tension to the tape as the cartridge is unloaded from thetransport mechanism. The tensioning arm 143 is urged in a clockwisedirection about pivot point 144 by means of a wire spring as indicatedat 540 so as to maintain the tape at path section 25 in a taut straightline condition.

In applying the cartridge 11 of FIG. 2 to the tape transport of FIG. 14,recesses at the underside of the cartridge are interengaged with theoverhanging fingers 304a and 305a of lugs 304 and 305, with thecartridge disposed at an angle and overhanging the rear edge 302a ofcartridge support 302. The interlock with the ledges 304a and 305apermits downward pivoting movement of the forward end of the cartridgeto an operating position with the cartridge resting on the pads 309-312.Spring fingers 313 and 314 serve to urge the cartridge rearwardly so asto insure interengagement of the cartridge with the lugs 304 and 305such that the rear edge of the cartridge cannot be lifted out ofengagement with the lugs 304 and 305. As the cartridge is pivoteddownwardly into the operating position, the tape path section 25, FIG.2, moves between the capstan assembly 301 and the capstan pressurerollers such as indicated at 323, FIG. 14. The transducer head for theembodiment of FIGS. -18 is indicated at 380 in FIG. 12, and is disposedgenerally as indicated for head 40 in FIG. 1 in the loading condition ofthe transport mechanism.

With the cartridge in the operating position, carriage 317, FIG. 14,together with the head indexing assembly 337 and the head 380 areactuated to an operating position as represented in FIG. 15. In theoperating position, the head 380 has its convex face as indicated at380a, FIG. 12, inserted into a vertical groove as indicated at 202 inFIG. 5 of the tape guide 200. A detailed showing of the relationshipbetween the pole pieces of the transducer head and the tape whichextends along the channel 201 of tape guide 200, FIG. 5, is found in thesecond figure of the copending application Ser. No. 60,806, and isapplicable with respect to each of the embodiments of the presentdiclosure.

As carriage 317 is advanced to the operating position shown in FIG. 15,capstan pressure rollers such as 323 are advanced so as to establish anoperating loop path for the tape, with the tape pressed into drivingengagement with the capstan at the periphery thereof such as indicatedat 212 in FIGS. 1 and 8 at each of the opposite sides of the capstan.

In the operating position of the transport mechanism, a tape drag suchas provided by components 94 and 96 in FIG. 3 acts at the incoming tapepath. The tape drag is operable to apply a drag force to the tape whichexceeds the momentum force on the tape at the outgoing tape path due tothe inertia of reel and the associated parts. By way of preferredexample, the tape drag elements such as 94 and 96 in each embodimentapply a relatively substantial drag force which in conjunction with thecapstan drive assembly provides a tape tension at the transducer head ina range from about 1 ounce to about 4 ounces for a 4 inch wide magnetictape.

In each embodiment, the incoming tape path such as indicated at 164 fromthe inner side of coil 128 to the incoming side of the capstan driveassembly follows a path having a total amount of bending ofsubstantially less than 90, and in fact less than 45, so as to enable arelatively free movement of the tape. The constant friction supplied bythe drag elements 94, 96 tends to swamp out any irregularities in tapemotion, for example, due to variations in the friction exerted by thecoil 128 as the tape is unwound from the inner side thereof, and isfound to be important in facilitating proper guiding of the tape overthe pressure rolls, the capstan and the head during operation of thesystem.

The capstan drive rollers in each embodiment preferably have theconfiguration shown in the seventh figure of said copending applicationSer. No. 60,806 for the purpose of establishing a substantial tension inthe tape loop being scanned by the transducer head. For example, thegroove in the capstan roller at the incoming side of the tape loop iswider than the tape and may have a depth of about 0.0015 inch, so thatthe tape engaging diameter of this capstan roller is about 0.003 inchless than that of the capstan roller at the outgoing side of the tapeloop.

In each embodiment, the outgoing tape path section such as indicated at165 in FIG. 3 has essentially zero tension but is sufficiently guided soas to pass in close proximity to the photocell assembly 28 or 303 whichcontrols the successive vertical indexing movement of the transducerhead. In the embodiment of FIGS. 1-9, each time the photocell assembly28 is actuated, solenoid 41 is momentarily energized to index theratchet wheel 43 through one increment of its movement, so as to shiftthe head 40 from the scanning of one channel longitudinally of the tapeto the scanning of the next adjacent longitudinal channel.

In the embodiment of FIGS. 10-18, each actuation of the photocellassembly 303 serves to close an energizing circuit for motor 330. Themotor rotates a drive train including worm 335 which in turnprogressively moves the head 330 in a vertical direction by rotation ofthe cam 371, FIG. 11, having the cam face 3710. This motor energizingcircuit is under the control of a switch operated by cam 332 which isincluded in the drive train, so that the motor 330 is deenergized at aprecisely determined position of the head 380 corresponding to the nextchannel on the tape. The cam 332 is provided with a notch controllingopening of this electric switch, and the notch has a sufficient angularextent, for example 30, so that the drive train will come to a stopwhile the cam actuating the switch is still in registry with the notchof the cam wheel 332, thus preventing the inherent momentum of the drivetrain from reclosing the switch and reenergizing the motor 330 when itis necessary that the motor come to a stop with head at the next channelto be scanned. The speed of the motor 330 and the reduction ratio of thedrive train to the head is such that the vertical indexing movement ofthe head between successive channels takes place over an intervalcorresponding to a substantial distance of travel of the tape, thegradual transition between successive channels as scanned by themagnetic head being illustrated in the ninth figure f U.S. Pat. No.2,857,164. An exemplary electric circuit is shown in FIG. A wherein thephotocell circuit 303 may include a suitable monostable drive forelectronic switch 542 such that each actuation of the photocell 303maintains switch 542 conductive for a sufficient time interval to insurethat motor 330 has driven cam 332 a sufficient angular distance so as toclose contacts 543 and 544. The electronic switch 542 may also be amonostable circuit with an on time such that the switch 542 will benon-conducting before notch 332a of cam 332 again comes into registrywith follower 543a. Then, as soon as notch 332a again registers withfollower 5430, the energizing circuit for motor 330 is opened and thedrive train is brought to a stop in a position of the cam 332 such asindicated in FIG. 15A.

By way of example, the reflecting element on the tape that actuatesphotocell 23 or 303 may be 1 4 inches long in the direction of tapetravel, giving a trigger pulse from photocell 303, FIG. 15A, lastingabout 0.01 second, when the tpe travels 120 inches per second. Theelectronic switch 542 may be a monostable multivibrator circuit which isactuated to the conductive state by the trigger pulse from photocell303, and which remains conducting at least until notch 322a is out ofregister with follower 543a and switch contacts 543, 544 are closed. Ifthe time to complete one revolution of cam 332 is 0.5 second, and ifnotch 332a has an extent of about 30, the switch 542, once triggered,may remain closed a time interval corresponding to at least 30 ofrotation of cam 332 or at least about 0.042 second. The electronicswitch 542 must open in less than 0.5 second in this example so that themotor 330 will be deenergized when cam 332 has made a completerevolution. For a tape speed of 120 inches per second, the tape travels60 inches during a channel changing interval of 0.5 second, giving a veygradual and unnoticeable transition. If a faster change is desired, thecam speed may be increased and the associated elements adjustedaccordingly. If motor 330 and the gear train (331, 333, 334, 335 and350) have a substantial lag in response to a trigger pulse fromphotocell 303, the electronic switch 542 is adjusted to provide acorrespondingly longer on time to compensate for the lag and insurereliable cycling of the motor 330.

Each of the illustrated embodiments is capable of operation at speeds of120 inches per second, or more, and with scanning ofa total of 40channels on a 5 inch wide tape without substantial cross talk.

In each of the embodiments, preferably the loop path extending from theincoming side of the capstan to the opposie outgoing side of the capstanhas a length less than the capstan circumference, the transducer headbeing arranged for scanning cooperation with the record tape in such away that the tape path conforms with the convex contour of he head asindicated at 380a, FIG. 12, but with an air space between thenon-magnetizable backing of the tape and the bottom of the groove 202such that the transducer head engages the record tape at an unbackedportion of the loop path. Alternatively a soft spongy pad may be securedin groove 202 and, for example, occupy the entire volume of the groove,so that the tape is resiliently backed in each scanning position of thehead, the pad having a cover of smooth low friction material tofacilitate smooth indexing movement of the head relative thereto. Asillustrated at 205 and 206 in FIG. 5, the tape guide channel may have aconvex contour over an extent of the tape guide surface corresponding toa major portion of the loop path of the magnetic tape from the incomingside of the capstan to the outgoing side of the capstan.

When the transport mechanism is shifted back to the loading position forexample as shown in FIG. 14, a microswitch finger 321 is released todeenergize the capstan drive motor, and operating finger 420 is releasedallowing spring 414, FIG. 16, to cause the application of the brake 405to flywheel 401, and the reel brake as indicated at 92 in FIGS. 2 and 3is released to allow spring 155, FIGS. 6 and 7, to exert a braking forceon the reel. Preferably where the reel has substantial angular momentum,the drag provided by elements such as 94 and 96 is released as thecarriage 317 is retracted to the loading position so that movememt ofthe tape is brought to a stop by means of the reel brake 92 at the sametime that the capstan is being stopped by means of capstan brake 405,FIG. 16. Preferably, the tape drag is substantially releasedapproximately simultaneously with the release of driving engagement between the capstan and the tape. Thus, the drag force on the tape isreleased generally contemporaneously with the release of engagementbetween the capstan and the pressure rollers. Preferably, the capstanflywheel brake is operable to essentially stop the capstan during theminimum time required to remove and replace a cartridge relative to thesupport, so that there would be no possibility of the capstan continuingto rotate at the time a new tape is engaged therewith. Most preferably,the capstan brake operates with sufficient speed so that the capstanwill stop rotating in approximately the time required for the reel brake92 to stop the movement of the magnetic tape, so that tape of thecartridge can be re-engaged with the capstan at any substantial timesubsequent to the actuation of the transport mechanism to the loadingposition after a playing operation.

upwardly about the lugs 304 and 305, FIG. 14, so as to remove thecartridge from the machine. An ejector (not shown) actuated by a pushbutton can lift the cartridge at the forward edge (against theresistance provided by spring fingers 34, 35, FIG. 3, or 313, 314, FIGS.14 and 15) to allow easy access to the cartridge. Spring fingers 34, 35,313, 314 would serve to retain the cartridge in the position to which itwas raised by actuation of the ejector. A cover 532 may be applied overthe open end of the cartridge 11 as shown in FIg. 18 so as to provide adust proof enclosure for the magnetic tape when the cartridge is not inuse.

EMBODIMENT OF FIGS. 19-26 Referring to FIGS. 19-26 there are illustratedfurther features which may be applied to any of the precedingembodiments for the purpose of facilitating manual shifting of thecarriage or 317 from the load to the operating position, for the purposeof automatically returning the carriage to the load position aftercompletion of scanning of all of the channels of a tape, where desired,and for the provision of other advantageous

1. In a transducer system including a capstan for driving engagementwith a record tape in an operating mode, said capstan having a flywheelrotatable therewith, capstan pressure roll means shiftable from aretracted position to an operating position to engage the record tapewith the capstan in the operating mode, a brake for the flywheeldisposed adjacent the flywheel and actuable into braking relation tosaid flywheel and thus to a capstan retarding condition for retardingrotation of the capstan, and a brake control coupled with said brake andoperable contemporaneously with retraction of said pressure roll meansfrom the operating position to actuate said brake to its capstanretarding condition, a driving motor for said capstan having a rotor andhaving a motor shaft secured with said rotor, said motor being operableto drive said capstan at a rotational speed corresponding to a recordtape speed of at least about 60 inches per second during said operatingmode, said flywheel being directly on said motor shaft and having itsouter peripheral surface coaxial with the axis of said motor shaft, saidcapstan being directly adjacent said flywheel along the length of saidmotor shaft without any intervening drive element, said brake for saidflywheel comprising a brake shoe physically movable toward and away fromsaid outer peripheral surface of said flywheel, and said brake controlcomprising a spring operable to press said brake shoe into directfrictional contact with said outer peripheral surface of said flywheelin the capstan retarding condition of said brake.
 2. In a transducersystem including a capstan for driving engagement with a record tape inan operating mode, said capstan having a flywheel rotatable therewith,capstan pressure roll means shiftable from a retracted position to anoperating position to engage the record tape with the capstan in theoperating mode, a brake for the flywheel disposed adjacent the flywheeland actuatable into braking relation to said flywheel and thus to acapstan retarding condition for retarding rotation of the capstan, and abrake control coupled with said brake and operable contemporanteouslywith retraction of said pressure roll means from the operating positionto actuate said brake to its capstan retarding condition, a supportassociated with said capstan for removably supporting an endless loopcartridge for transducing operation with the record tape thereof indriving engagement with said capstan, said brake control being operableto essentially stop said capstan during the minimum time required toremove and replace a cartridge relative to said support.
 3. In atransducer system including a capstan for driving engagement with arecord tape in an operating mode, said capstan having a flywheelrotatable therewith, capstan pressure roll means shiftable from aretracted position to an operating position to engage the record tapewith the capstan in the operating mode, a brake for the flywheeldisposed adjacent the flywheel and actuatable into braking relation tosaid flywhel and thus to a capstan retarding condition for retardingrotation of the capstan, and a brake control coupled with said brake andoperable contemporaneously with retraction of said pressure roll meansfrom the operating position to actuate said brake to its capstanretarding condition, a support associated with said capstan forremovably supporting an endless loop cartridge including a rotatablereel for carrying a coil of a record tape, the reel being rotatablydriven by means of the engagement of the capstan with the record tape inthe operating mode, and a reel brake control for controlling theapplication of a braking force directly to the reel of a cartridge onsaid support and operable contemporaneously ith the release of drivingengagement between the capstan and the record tape to effect theapplication of a braking force to the reel at least great enough to stopthe rotation of the reel in approximately the time required for theflywheel brake to bring the capstan to a stop.